Assessing the effect of tsunami-induced vertical loads on RC frames

The increasing number of people, structures and economic activities being exposed to tsunami hazards makes it important to estimate the effects of this hazard on coastal developments. Tsunami onshore flow generates significant loading on buildings and infrastructure, which can lead to structural failure. Literature works recently proposed a non-linear static analysis method, called Variable Depth Pushover (VDPO), for assessing the performance of buildings under the lateral pressures induced by a tsunami onshore flow. This methodology was developed under the assumption that the building is watertight. However, in the case of buildings with breakaway cladding (e.g., masonry infills), the water flow passing through the building induces vertical loads on horizontal structural members, due to uplift and buoyancy pressures, that should be considered during the analysis. Thus, to address this phenomenon, in this paper a numerical investigation is performed considering a combination of tsunami-induced horizontal and vertical loads on a case-study reinforced concrete (RC) moment-resisting frame with breakaway infills, typical of Mediterranean construction. The building model is subjected to a VDPO analysis that applies different types and sizes of vertical loading on the horizontal elements of the building, as the tsunami inundation depth increases. From the results of this analysis, the effects of tsunamiinduced vertical load components on the case-study building in terms of damage propagation and failure mode are discussed, and the significance of considering vertical loading is proven

Deriving optimal operational policies for off-stream man-made reservoir considering conjunctive use of surface- and groundwater at the Bar dam reservoir (Iran)

Study region: The off-stream artificial Bar lake, built in 2015 to store the flood flows of the Bar river for domestic and industrial needs and with the objective to intentionally recharge the aquifer, is situated in the Razavi Khorasan province (Iran). Study focus: We present a methodology, based on the combination of a MODFLOW groundwater flow model for estimating seepage rates, and an optimization model, for the management and operation of an artificial reservoir considering surface/groundwater interactions for satisfying 12 Mm3/year of water demand. We simulated the reliable amount of water that can be supplied from the reservoir, considering reservoir seepage, maximizing water supply yields subject to the water supply reliability requirements, and the additional intentional volume of groundwater recharge. New hydrological insights for the region: Our results demonstrate the reliability of conjunctive use of surface-and ground-water in water scarce areas by exploiting reservoir infrastructures with relevant leakage losses, also for creating additional aquifer storage. In such systems, man-induced changes of lake stages can significantly affect the volume of water that seeps through the lakebed. The aquifer, under managed aquifer recharge operations, may then provide the resource not satisfied by the reservoir release, fulfilling 100 % reliability of water supply. The conjunctive use of surface- and ground-water, by improving water security, may open new sustainability views for leaking reservoirs, even if they were not initially designed for increasing aquifer recharge, in many areas worldwide

Image counter-forensics based on feature injection

Starting from the concept that many image forensic tools are based on the detection of some features revealing a particular aspect of the history of an image, in this work we model the counter-forensic attack as the injection of a specific fake feature pointing to the same history of an authentic reference image. We propose a general attack strategy that does not rely on a specific detector structure. Given a source image x and a target image y, the adversary processes x in the pixel domain producing an attacked image (x) over tilde, perceptually similar to x, whose feature f((x) over tilde) is as close as possible to f (y) computed on y. Our proposed counter-forensic attack consists in the constrained minimization of the feature distance Phi(z) = vertical bar f (z) f (y) vertical bar through iterative methods based on gradient descent. To solve the intrinsic limit due to the numerical estimation of the gradient on large images, we propose the application of a feature decomposition process, that allows the problem to be reduced into many subproblems on the blocks the image is partitioned into. The proposed strategy has been tested by attacking three different features and its performance has been compared to state-of-the-art counter-forensic methods

VHCF Response of H13 Steels Produced with Different Manufacturing Processes

Experimental results have recently shown that failures at stress amplitude below the conventional fatigue limit and at Very High Cycle Fatigue (VHCF) are possible. In case of high-strength steels, VHCF failures generally originate from defects/inclusions present within the material and, consequently, the defect population properties (size and quantity) significantly affect the VHCF response of high-strength steels. Different refinement processes are commonly adopted in order to improve steel cleanliness: among the other, the ElectroSlag Remelting (ESR) process allows to obtain very clean high-strength steels, thus possibly inducing a significant enhancement of the VHCF response. The present paper aims at investigating the actual effect of the ESR process on the VHCF behavior of an AISI H13 steel. Fully reversed ultrasonic tension-compression tests are carried out on hourglass specimens manufactured with and without the ESR process. The estimated P-S-N curves highlight the positive effects of the ESR process on the VHCF response of the investigated H13 steel

Looking for hotspots of marine metacommunity connectivity: a methodological framework

Seascape connectivity critically affects the spatiotemporal dynamics of marine metacommunities. Understanding how connectivity patterns emerge from physically and biologically-mediated interactions is therefore crucial to conserve marine ecosystem functions and biodiversity. Here, we develop a set of biophysical models to explore connectivity in assemblages of species belonging to a typical Mediterranean community (Posidonia oceanica meadows) and characterized by different dispersing traits. We propose a novel methodological framework to synthesize species-specific results into a set of community connectivity metrics and show that spatiotemporal variation in magnitude and direction of the connections, as well as interspecific differences in dispersing traits, are key factors structuring community connectivity. We eventually demonstrate how these metrics can be used to characterize the functional role of each marine area in determining patterns of community connectivity at the basin level and to support marine conservation planning

Statistical estimation of fatigue design curves from datasets involving failures from defects

In the present paper, two methodologies for the estimation of the design curves of datasets with failures originating from defects are proposed. With the first methodology, the Likelihood Ratio Confidence Bound of a specific quantile P-S-N curve is considered. The second method is based on the bootstrap approach, with a large number of datasets simulated starting from the stress life and the defect size distributions estimated from the experimental data. The two approaches have been validated on literature datasets covering also the Very High Cycle Fatigue (VHCF) life region, proving their effectiveness

Impacto do manejo da palhada sobre sua decomposição em área cultivada com cana-de-açúcar no município de Guaíra-SP.

O presente trabalho tem como objetivo acompanhar a dinâmica e as taxas finais de decomposição de diferentes quantidades de palhada de cana-de-açúcar, sob condições de Guaíra-SP. Para isto foi conduzido um experimento em área comercial de cana-de-açúcar, variedade RB 86-7515 na safra 2012-2013, em primeira soca. Como tratamentos foram testados os níveis T(25%), T(50%), T(75%) e T(100%), correspondentes a 4,7; 9,4; 14,1 e 18,8 t ha-1, distribuídos em blocos ao acaso, em quatro repetições. Para o acompanhamento da decomposição avaliou-se a quantidade (t ha-1) e a taxa (%) da massa seca remanescente no solo em coletas realizadas aos: 0, 63, 125, 189, 230, 285 e 328 dias após a instalação; utilizando-se de sacos de serapilheira ("litter bags") nas dimensões 0,50 x 0,75 com 15 mm de abertura. O tratamento estatístico foi feito por análise de variância, regressão e equações de cinética para ajuste do comportamento da decomposição da palhada. Os resultados permitiram concluir que os níveis de palhada alteram a dinâmica da decomposição deste resíduo, sendo o coeficiente de decomposição (K) significativamente superior para os níveis 100% e 75%. As maiores taxas de decomposição ocorrem até os 189 dias do ciclo, sendo mais lenta a partir deste ponto; com média de 41% de massa remanescente aos 328 dias, independente do nível de palhada. Abstract: The project aims to evaluate decomposition dynamic of different inputs of sugarcane straw under conditions of Guaira-SP. The experiment was conducted in a first ratoon commercial area of sugarcane, variety RB 86-7515, in 2012-2013. The treatments were tested by the levels of (25%), T(50%), T(75%) and T(100%), corresponding to 4,7; 9,4; 14,1 and 18,8 t ha -1 , arranged in a randomized block design, with four replications. The development of decomposition was evaluated using the quantity (kg ha -1 ) and the rate (%) remaining of dry matter, evaluated at: 0, 63, 125, 189, 230, 285, 328 days after installation by the use of litter bags (0,75m x 0,50m x 0,015m). The data were analyzed by variance, regression and kinetic equations for adjust the residues decomposition behavior. The results show that the levels of straw can modify the dynamics of this residue decomposition; the decomposition coefficient (K) was significantly higher for the levels of 100% and 75%. The highest rates of decomposition occur until 189 days of the cycle, being slower from this point; averaging 41% to the 328 days (harvest), regardless of the level of straw

Effects of the Environment on the Properties of Seyfert Galaxies

We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire SSRS2 catalog to investigate the correlation between the presence of AGN with host environment. The AGN phenomenon is more strongly correlated with the internal host properties, than with the external environment. In particular, we find that Seyferts reside in more luminous galaxies, and are twice as frequent in barred galaxies and systems showing sign of advanced merger condition, when compared to a control sample.Comment: 4 pages, 3 figs, 1 tables, to appear in the proceedings of "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", IAU 222, eds. T. Storchi Bergmann, L.C. Ho, and H.R. Schmit

VHCF response of heat-treated SLM Ti6Al4V Gaussian specimens with large loaded volume

Abstract Among the materials used for the production of components through Additive Manufacturing (AM) processes, the Selective-Laser-Melting (SLM) Ti6Al4V alloy is widely employed in aerospace applications for its high specific strength and in biomedical applications for its good biocompatibility. Actual structural applications are generally limited to static loading conditions where the large defects originating during the SLM process do not play a significant role for the static failure. On the contrary, the same defects strongly affect the fatigue response of the parts since they act as crack initiation sites that rapidly lead to fatigue failure. In the literature, a lot of research has been carried out to investigate the quasi-static and the High-Cycle Fatigue properties of the SLM Ti6Al4V alloy but there are still few studies on its Very-High-Cycle Fatigue (VHCF) response. In the paper, the VHCF response of Ti6Al4V specimens, which are vertically orientated during the SLM building and then subjected to a conventional heat treatment (2 hours heating in vacuum at 850°C), is experimentally assessed. Ultrasonic VHCF tests are carried out on Gaussian specimens with a large risk-volume (2300 mm3). Fracture surfaces are investigated for revealing the defect originating the fatigue failure. The Stress Intensity Factor Threshold associated to the experimental failures is finally estimated